Yamashita had an abnormal love for his younger sister Nana (bordering on a sister complex), showing jealously for when she friends with males and willing to go to prison for her crime. The first thing he did after escaping prison was try to get back in touch with Nana so he could protect her.

Yamashita had went to prison for his Nana's crime of killing her fiance having a motive and loyalty to do so. In prison, Yamashita was given a special gun that allowed him to escape from the guards. When Nana along with Seiji Hayami tried to find him, Yamashita tries to reconnect with Nana. While driving in a stolen car, Nana had stabbed Yamashita trying to get him to take the fall again. When the police catch up, Yamashita attempts to do so. However Panther Claw combatants show up to kill Yamashita for being wounded. While Yamashita held one of them down for Nana to get away but is killed afterwards.